In recent years there have been developments to provide adjustable step devices as well as steps which are retractable when not in use. Most of these inventions are somewhat mechanically complex or require the user to manually return the step to its stored position.
Le Guillon, U.S. Pat. No. 3,986,503, 1976, provides a mounting means for machines comprising a bracket and step assembly. The pivotal bracket may be lowered to a secured horizontal position and by manually disengaging the locking means, the bracket will return via a spring, to its vertical stored position.
William Bingham, U.S. Pat. No. 4,132,288, 1979, has developed a ladder with retractable rungs. A plurality of rungs may be hingedly secured to a central stem which is secured within an elongated housing.
A most recent development has been that of Peter Buche, U.S. Pat. No. 4,402,385, 1983. Buche has developed a folding step which uses a mounting plate and elongated step member. The step member is manually raised from its operative horizontal position and secured within the bracket member in a relatively vertical position when not in use. Cooperating means are provided on the mounting plate and step member to store the step member and keep it from passing through the opening or recess in the mounting plate while being stored.
A major disadvantage of these inventions is that when not in use, the steps will not be automatically retracted or stored in a recessed position from their mounting means. In warehouses and other industrial sites, for example, machinery and vehicles are often traveling back and forth proximate to structures which may utilize folding and retractable step devices. This is particularly true in a warehouse where front loaders and fork lift trucks are traveling in the aisles between large storage racks or scaffolding structures. With a load partially obstructing his view, the vehicle operator will often not see the step member projecting into the aisle way or roadway space of the vehicle. Consequently, an unattended step device left in an extended or horizontal position is often struck and broken off by the loading vehicle.
A projecting step device which is not being used can also provide a dangerous obstacle to workers passing by who might not see the step while carrying a load for example.
An object of the present invention is to provide an automatically retractable step assembly which will store the extended projection in a recessed position behind its mounting means to prevent the step from accidentally being sheared off by passing vehicles and prevent injuries to passing pedestrians. A further object of the present invention is to provide a step assembly which uses a minimum of components and requires virtually no maintenance with regard to parts which may need to be replaced in order to provide its automatic retractability. It is a further object of the present invention to provide several embodiments of the invention so as to permit some flexibility in adapting the step assembly to various sized and shaped mounting structures.